After registration login form

Yes, the login form (or registration form) can be customized. That’s a pretty broad topic since you can change just about anything in the forms via the plugin’s filters and also layout via CSS.

So if you’re just talking about layout, there is information on customizing the stylesheet here:
http://rocketgeek.com/plugins/wp-members/docs/customizing-forms/

If you’re talking about other elements, there are quite a few filters for the various elements of the form. All supported filters are documented here:
http://rocketgeek.com/plugins/wp-members/docs/filter-hooks/

There is only one login form – the same function is used whether it’s produced via the shortcode, displayed in place of blocked content, or at the end of successful registration. However, the automatically produced forms won’t be affected by the redirect that you have in the shortcode (that would only apply to that single instance of the form).

You can apply a redirect using the wpmem_login_redirect filter:
http://rocketgeek.com/plugins/wp-members/docs/filter-hooks/wpmem_login_redirect/